Christa Ludwig may be turning 89 tomorrow (March 16) but she shows no sign of losing her edge or her sense of humour. In a frank and wide-ranging interview with Christian Berzins for the Swiss publication NZZ on Sunday, the great German mezzo soprano talks frankly about her career and her art, while delivering the odd serve to the likes of Anna Netrebko and Fritz Wunderlich.

“Nowadays, in the supermarket, when somebody approaches me and says: ‘You gave me so many happy hours,’ I begin to cry. That’s what moves me, that’s the only thing that counts,” she says, beginning with what might seem a sentimental exchange. But she soon toughens up, humbly dismissing her career as “so-called”. Although she might admit that she’d had the odd “beautiful” moment in performance, she rapidly dismisses such thoughts as “egoism”, and when the interviewer suggests that performers seek admiration from audiences, replies: “No, for God’s sake! That would be terrible.”

Unusually, for a famous opera singer, she admits that opera never really interested her with the possible exception of Wagner or Strauss. “But all the Italian operas of Rossini, Donizetti, and Verdi: Is that really art?” she says. Asked...